Block-signal system.



Z SHEETSSHEET 1.

ENS.

iatented Mar. 2 1, 191A L. A. HAWK BLOCK SIGNAL SYSTEM.

APPLIUATION nun) JULY 5.1910

ntor:

ZOZZW His flttofneg.

ilfive Laurence f1. Hawkins, by M Witnesses:

UNITED STATES OFF-ICE.

LAURENCE A. mwxms, or s'cnnmimrpmtqgonx, Assmnoa, BY MESNE ASSIGNMENTS, 'ro ms muon swrrcn m SIGILL GOIPANY, A CORPORATION OF PENNSYLVANIA;

BL'ocx-smnu. srssrnu.

Specification of Letters Patent. 5 t t 24, 914

Applfcatlon filed July 5. 1910. Serial No. 570,260.

To alt whom it may concern Be it known that I, LAURENCE A. HAW- KINS, a citizen of the United States, residing at Schenectady, county, of Schenectady, State of New York, have invented certain new and useful Improvements in Block- Signal Systems, of which the following is a specification.

My invention relates to block signal systems and particularl .to 'si al'sy'stems opy i entrance of the blocks.

erated'by alternatingcurrent In my prior ap"l.i"ca'tion Serial .No. 511,663, filed Augug -7, 1 909, 'I have disclosed an alternating current block signal system in which the signals are arranged to give the three indications of danger, caution, and clear, and are controlled without line wires by contact for shifting the phasev of the alternating current in the track circuit; two relays being provided for each block. each relay being of the type having two 00- operating windings, one connected to the track and the second 'suppl' with current independently of the trac circuit. The

currents'inythe second windings of the rela ys of each pair were of different phase, so

that one relay was effected by the variation inph'ase of the track current while the other remained unaffected thereby. One of these relays controlled the caution and the other the clear indication of the signals.

In the system of my prior application allthe signals and relays "were placed at the entrance of the blocks, When the blocks p v e byto. shift the phase of the teach wheat, in

the long many signal engineers prefer wefthecaution indication by a distant s gnal-.;.-placed atsanjintermediate pointin 't e biok" for, the that if the caution in.-

. wdication is given at the entranceofaa long flock, so that it is notcnecessar'y for a long.

'when the stunt signal is' was assne pp l :an'nderstanding of my 1nvention reference may be had to the accompanying drawings, in which- Figure 1 shows diagrammatically a block signal systemarranged in accordance with my invention, and Fig. 2 shows a modification thereof. I

In Fig. 1, A represents thejtrack rails which are separated at the ends of the blocks in the usual manner by insulated joints 0, B, B and 13 represent home signals at the B and B represent distant signals atintermediate points in the blocks; C represents a three-phase transmission system through which the alternating current is supplied for the signal system. D, D. and D represent transformers at the home signals. These transformers are arranged withthewell-known .threehase, two-phase connection, so that two-p as'e voltages are delivered by their secondary! windings; D -and D are singlephnse transformers at the distant signals.

and E representtrack transformers,

the primaries of which are connected to the secondaries of the transformers D,-.D and D, through contactel), bf, and b actuated by the signals B, B, p respectively. The secondaries of these transformers are connected to the track rails and supply alternating current thereto; The fsfglurpoee of the contactslb, b and Pie a) f 'ft the transformers from one phase to the other of the transformers D, D and D andth reof preventing an excessive ciirrent flowing. when the secondaries of the track transformers are short-circuited by trains;

connections of the primaries'aof the track .Ihese impedances serve the double pu ggse and of permitting the primary of thetiack transformer to be connected tothe phase 'of the line ftransformers'b efore connection 'to the first phase is brakes.

Thus the relays are not even momentarily de'nergized when the connections of the track transformers are changed. F, F

of the blocks controlling the home signals trackrela s' located at the dis t s ""eontrolling t ggigta f and F represent track relays at the cntra'ncesif of the track relays is shown diagrammatij resented by 0z'f in the vector diagram him t for closing its contacts when the current in and by gravity. In relay F the current in necessary to give the relay a torque, the en-- upon the relay. \Vith signal B, at stop position, the contact b connects the primary of lay, consequently, are displaced by approxically as of the well-known induction type comprising a short-circuited secondary member f carrying the relay contacts, a winding 5 f connected to the track rails, and a second winding f supplied with current independ I ently of the track rails f in the transformers D, D and D The winding f of relays F and F is connected across an insulated joint (1'' inserted in the track rail. The same winding of relays F, F and F is connected acrossthe track rails in the usual manner. The track windings'of relays F and F are thus inserted in the track ci cuit between the transformer and the relay at the end of the track circuit controlling the home signal. Beneath each relay is placed a vector diagram indicating the electrical conditions in the windings of the relay. Relay F is short-circuited by a train, indicated. at G, so that its track winding f is deenergized, thetrelay contacts are open, and the signal B is at-stop. position. The winding f is energized as is, indicated in the vector diagram below this relay, 0-wf indicating the voltage impressed on this winding and 0--if representing the current lag ging nearly degrees behindcthis voltage because this winding is highly inductive.

Since the coiiperation of both windings is ergization of winding f alone has no effect track transformer E across the right-hand secondary of the polyphase transformer D. This is. the same phase as that to which winding f of relay F is connected but the track circuit has a much higher power factor than the winding f, so that the current in the secondary of transformer E may be repmediately below relay F This is the cur rent in the winding f of this relay. The winding 1 of this relay is connected to the secondary of the transformer D which impresses upon it a voltage displaced 90- from the voltage impressed on the corresponding winding of relay F. The voltage and cur rent in winding f of relay F may,-consequently, be represented by 0-4 and o-e'fi, respectively, in the diagram below the relay. The currents in the two windings of this remately 45 degrees If the relay is so arranged that it has a torque in the direction the track winding leads the current in the other winding, then with the relative current phases existing in relay F the relay will have a reverse torque and its contacts will be held open both by its reverse torque the track winding 7" is the same as in the corresponding winding of relay F and is,

% ing f of this relay is connected the same as the corresponding winding of relay F, so that its voltage and current may be repre- .sented by 0-17" and 0-Zf respectively 1 V thatsthe relay is energized wit a torque which closes its contacts and signal is cleargd. \Vith signal B in clear position, contact b connects the primary of ("ans former E to the left-hand secondary of transformer D. The voltage in the track circuit in which transformer E is connected is, therefore, 90 displaced from that in the track circuit next in advance. The current in winding f of both relays F and F may, therefore, be represented by 0-f in the diagrams beneath theserelays, c-if in these diagrams being displaced 90 from 0--13 f in the diagrams below relays F and F. The conditions in the windings f of relays F" and F are precisely the same as in the corlay F and approximately 135 .degrees iiu' relay I. Both of these relays, are, consequently, energized and both distant signal B and home signal B are cleared.

With the arrangemen shown onl two relays are required for the dontrolo the sig nals and no line Wires, except thc transmission lines, are required. With rer long blocks, or when the ballast is poor, sol that the track leakage is high, it may be desirable to employ two track circuits per block. In such a case the arrangement shown in Fig. 2 may be employed. In this arrangement one track circuit extends from home signal B to distant signal B and the other from distant signal B to home signal B, the two track circuits constituting a single block; In this case it is necessary to provide an additional relay since a relay for controlling the home signal must be included in the track circuit between signals B and 13'. This relay control the connections of the track circuit between signals B and B, so as to control the relay at the signal B. The connections ofthe windings of relays F, F and F are precisely the same in Fig. 1, so that the vector'diagrams for these relays are the same as in Fig. 1. Relay F controls through its contacts the circuit of track transformer E ,v'hcn'the relay F is short-circuited by a train its contacts are open and the primary circuit of transformer is broken, so that the track circuitof relay F is deenergi aed Thus relay is deencrgized by a train at any point between signals B and 13. In order to giver eliry F? the maximum torque, the connections between the two secondaries of transformer D and the primary of transformer E may be arranged as shown so that the voltage im- 5 pressed on the primary of transformer E is the result-ant of the two secondary voltages of transformer D With this connection the current in winding f of relay 15 will be as represented by 0-'if' in the diagram below it, that is, 45 degrees from the track current approximately 90 degrees, as shown in the vector dia am below this relay and will thus give t e maximum torque. The operation of this modification will be obvious from the drawing and from the description which has already been given in Fig. 1.

I do not desire to limit myself to the particular connecting and arrangements of parts shown, but aim in the appended claims to cover all modifications which come within the spirit and scope of my invention.

\Vhat I claim as new and desire to secure by Letters Patent of the United States is:-

1. In a block signaling system, home sig nals at the entrances to the blocks, distant signals at intermediate points in the blocks,

track circuits for the blocks, means controlled by the presence and absence of a train in a block for supplying one phase or another of current to the track circuit in the rear of said block, track relays directly controlling the distant signals and track re controlling the home signals, each track relay, having two windings cotiperating to close the relay contacts, one of which .w1n dings is connected with the track rails, means for supplying the second winding of each distant signa relay with current of a phase which will cooperate with one only of the phases in the track rails to close the relay,

and means for supplying the second win ing of each home si a1 relay with current of a phase which wi l cooperate with either phase in the track rails to close the relay.

2. In a block signaling system, home signals at the entrances to the blocks, distant signals at intermediate points in the blocks, tra k circuits for the blocks, means controlled by the presence and absence of a train in a block for supplying one phase 'or another of current to the track clrcuit in the rear of said block, track relays directly controlling the distant signals and track relays controlling the home signals, each track relay having two windings cooperati to close the relay contacts, an insulated oint inserted in a track rail of each block, one winding of each distant signal relay being connected across the adjacent insulated joint and one winding of each home signal relay being connected across the track rails, means for supplying the second winding of each distant signal relay with current of a phase which will cooperate with one only of the phases in the track rails to close the rela and means for supplying the second winding of each home signal relay with current of a phase which will cooperate with either phase in the track rails to close the relay.

In witness whereof, I have hereunto set my hand this 2nd day of July, 1910.

LAURENCE A. HAWKINS.

WVitnesses HELEN Onronn, BENJAMIN B. HULL. 

